Dfco

[reformed]

Do the manufacturers do DFCO in manual vehicles? I am wondering if my 92 civic 5 sp has this, anyone know?

[SVOboy]

What is DFCO?

[SVOboy]

Oh wait, is that cleanmpg's stupid name for engine braking?

[reformed]

Deceleration fuel cut off. Supposedly, on these cars it should kill fuel when in gear and decelerating down to 1000 RPM, but I don't know how the car would know if you were in gear or not. An automatic I can understand but I'm not too sure on a manual.

[SVOboy]

It's called engine braking. When you're in gear and take your foot off the gas and the engine slows the car down, you are not using any fuel. Any manual can engine brake, and some automatics will do it as well.

"DFCO" is a name some idiot made up for engine braking to make it sound like something magical he discovered.

[reformed]

Yep, you're right. One of these days I'll learn to google before opening my mouth (does that phrase apply to the internet?). I also just learned a technique for figuring out if you have DFCO in your car. I'm about to try this out on the way back to work so this is secondhand info as of this posting:

How to tell if your car has DFCO

Be careful with this test as you may lose Power Steering and Power Brakes during it! Choose the right time and location to perform the test.

On any level or slightly downhill road get up to at least 40 MPH, then start engine braking by keeping the vehicle in gear and letting all the way off the throttle while keeping the clutch disengaged (MT) or keeping the transmission in a gear lower than D (AT). Notice the deceleration force and the sound of the engine.

Now tun off your ignition (This is where you may lose your PS/PB, so be wary!) and watch for any harsher deceleration or change in the pitch of the engine for a few seconds.

If nothing was any different with the ignition turned off then your vehicle uses DFCO. If it decelerated at a different rate or pitch with the ignition off then it does not use DFCO. Do not forget to start your engine back up! But, do not try to start your engine back up (with the starter motor) while the car is moving and in gear. Just putting the key on run will cause the engine to "restart"

[blownintegra]

yes. I know from tuning these cars that under hard decel it will shut off the injectors. not sure of the threshold

[reformed]

Yea I definitely have to find the parameters of that before I can use it fully to my advantage. The consensus seems to be in the neighborhood of 1000-1200 RPM and above it will kill them for most cars, so for now I'm just going to stick with a guesstimate of about 1k and see what happens.

[blownintegra]

that sounds about right, and it will depend on the vacuum the engine pulls

[ttoyoda]

If nothing was any different with the ignition turned off then your vehicle uses DFCO. If it decelerated at a different rate or pitch with the ignition off then it does not use DFCO. Do not forget to start your engine back up!

Do not try to start your engine back up (with the starter motor) while the car is moving and in gear. Just putting the key on run will cause the engine to "restart"

I know YOU know this, but someone else reading this site might not.